This invention relates generally to refrigeration systems and, more particularly, to purge recovery systems for removing non-condensable gases from the refrigeration circuit thereof.
By removing water and non-condensable gases such as air from refrigeration systems, purge units improve refrigeration efficiency by ensuring that condenser pressure is not artificially high due to the presence of non-condensables.
Such a purge unit commonly concentrates air from the refrigeration system by using the temperature difference between the evaporator and the condenser (i.e. thermal purge). Refrigerant containing a small amount of air is bled from the condenser, through an orifice and into a small chamber containing a cooling coil which is maintained at the temperature of the evaporator by flashing refrigerant liquid from the condenser down to the evaporator temperature. As the refrigerant condenses and drains back to the evaporator through a float valve, the air remains in the purge chamber and becomes concentrated. As the air accumulates, the pressure increases, and eventually the air is evacuated by way of a small vacuum pump. With such a process it is difficult to entirely remove the refrigerant from the non-condensable gases by way of the condensation process and, as a result, there is some refrigerant that is released to the atmosphere along with the non-condensable gases. Not only is this a waste of refrigerant which must eventually be replaced, but it also contributes to the undesirable emissions to the earth's atmosphere.
One known method of increasing the efficiency of the condensation process in the purge chamber is that of using a compressor to increase the pressure in the purge chamber. This has the effect of allowing more refrigerant to condense and thereby leaving a lower concentration of refrigerant in the non-condensable gases that are vented to the atmosphere. However, this enhancement concept is somewhat limited by the practical considerations of the relatively high pressures that are necessary in order to obtain complete condensation of all the refrigerants in the purge chamber.
It is therefore an object of the present invention to provide an improved purge recovery system for a refrigerant circuit.
Another object of the present invention is the provision in a purge recovery system for decreasing the percentage of refrigerant that is trapped within the non-condensable gases that are released to the atmosphere.
Yet another object of the present invention is the provision in a purge recovery system for enhancing the recovery of refrigerant in the purging process.
Yet another object of the present invention is the provision in a refrigeration system for a purge recovery system that is economical to manufacture and effective and efficient in use.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken into conjunction with the appended drawings.